if the casino is bad in your country (although I am not sure), why did you create an account there and deposit money to play? this is quite surprising to me. instead of choosing a trusted casino in your country, you chose a casino with a bad reputation in your country. it is like you are intentionally donating your money.
your account was locked after you did KYC, I think there is a possibility that you are indeed having problems. Have you read all the casino's terms and conditions? there are several points regarding account cancellation, termination, and suspension. I hope you have not violated one or more of them.
https://bitcointalksearch.org/topic/bk8-is-a-big-scamsite-5507679
I didn't see VietNam in the list of restricted countries.
https://www.bk8asian.com/terms-conditions/
I'm not even sure if the terms are updated because the Philippines is listed as one of the restricted countries, yet they’ve been promoting this casino in the Philippines. In fact, they partnered with Manny Pacquiao, so they likely spent a lot of money on that.